The Pub Philosopher notes that new guidelines will permit moslem women to appear in court in disguise.

Update:

A little research throws up this judgement from the Court of Appeal, wherein we note that, in the UK, there is no right to confront ones accusers face to face. This is true both under national law and under the European Convention on Human Rights. Under the ECHR, however, the accused has the right

to obtain the attendance and examination of witnesses on his behalf under the same conditions as witnesses against him.

This appears to mean that all defence witnesses could appear in disguise too. While this would even up the playing field, I'm not sure that having all the lawyers and witnesses wearing tatty sacks over their heads is going to add a great deal either to the dignity or the efficacy of the trial.